As is well known, a magnetic tape device which uses a magnetic tape as a recording medium is one of external storage devices of a computer. As a mainstream magnetic tape device, a magnetic tape cartridge in which a magnetic tape with a width of several inches is included, the magnetic tape is automatically pulled out from a reel in a case, and it is loaded is used extensively. The required quantity of the magnetic tape cartridges is loaded in a magnetic tape library device (hereinafter, referred to as a library device) and the magnetic tape cartridge is selectively loaded into a magnetic recording/reproducing device (hereinafter, referred to as a drive) to read and write data.
The library device includes a medium storing shelf (hereinafter, referred to as a magazine) in which a plurality of cells for storing a recording medium are provided, an accessor which is positioned to a position facing a target cell in the magazine to pick up the recording medium from the facing cell that is the target cell or store the recording medium in the facing cell, and a drive which reads/writes data from/into the recording medium supplied by the accessor.
In this kind of library device, it is required to improve the storage capacity per unit volume as a basic performance. To meet this requirement, the cells in the magazine have to be densely disposed. In this case, highly accurate relative positioning between the cell in the magazine and the accessor is required.
On the other hand, variation in the relative positional relationship between the cell in the magazine and the accessor which is caused by tolerance of each of the components of which the library device is composed and an assembly error occurs. There is a possibility that the variation becomes large by a secular change of the above-mentioned components or the like. For this reason, in order to ensure highly accurate relative positioning between them, an adjustment is required before the device is actually operated and after the magazine or the like is added or replaced.
In order to adjust the relative position between the cell in the above-mentioned magazine and the accessor, a method disclosed in PLT 1 is commonly used, by which when the recording medium cannot be normally moved (picked up from/stored in the cell), the accessor is moved many times from a reference position to other positions until a position at which the recording medium can be normally picked up from and stored in the cell is found, wherein the accessor is moved by a predetermined amount for each movement.